Hi,

This John's way seems good. When making the patch, overlap the FG piece with the old one and it will be good in strenght;

: How to cure it? Most drastic: Redo it by taking it all off. Heat it with a
: heat gun and then pull up the fibreglass as the epoxy begins to soften,
: sand lightly, but not into the wood, and reglass. Or less drastic and
: better and easier, cut it out and stick in a patch. It will be invisible
: after you epoxy it in and almost as strong.
: JohnK

But... If you have large patches where fiberglass is slowly delaminating, you really should find the reason why. If there's a spot of contamination of somesort, it's only a spot. In your case you said the area is getting larger which tells that fiberglass is not glued properly. So I would try to find the reason. Was the wood too moist? Did the wood have oils or something in the surface? Did you wash and scrub the amine blush well (most common reason for delaminations)? You did say something about washing epoxy cups...

So, I would start from the patches, pulling the FG until you reach a point where it's properly glued. If it's easy to remove, then redoing fiberglass work is starting to sound necessary. But before doing the whole work again, think why it went wrong.

You might also try to find a specialist in your area to help you out.

Toni.